Interface for limiting substrate damage due to discrete failure

ABSTRACT

An apparatus is provided with a component configured with an interface comprising a resilient material. In a first state, the component is mechanically and/or electrically attached to a substrate. Exposure of the interface to the temperature that meets or exceeds the transition temperature of interface causes the resilient material to undergo a state change. The state change of the interface alters the position of the component, including separation of the component from the substrate. The separation disrupts the attachment thereby mitigating damage to the substrate and/or component.

BACKGROUND

The present embodiments relate generally to mitigating damage to asubstrate. More specifically, the embodiments relate to an interface tofacilitate separation of a failing component from the substrate prior tothe substrate and/or failing component experiencing damage.

The substrate is configured to support electronics and/or electricalenergy. An example of the substrate comprised of a conducting materialincludes, but is not limited to, a printed circuit board (PCB). Theconducting material is utilized to electronically connect componentsoperatively coupled to the substrate, such as resistors, capacitors, andother devices. Exposure of the substrate to damage may requirereplacement of the substrate. Similarly, exposure of one or more of theconnected components to damage may require replacement of the affectedcomponent(s), one or more proximally positioned components, and/or insome circumstances the substrate.

It is understood that a discrete component in communication with thesubstrate may experience a failure, such as an electrical short, whichcauses excess current to be driven through the discrete component and/orthe substrate. Excess current leads to resistive heating and subsequentthermal runaway leading to smoke, fire, failure of the component,failure of a PCB trace, failure of the PCB, and/or damage to thesurrounding devices.

SUMMARY

The disclosed embodiments pertain to mitigating potential damage to adiscrete component and/or a proximally positioned substrate by utilizingan interface which separates the failing component from the substrateprior to the substrate experiencing damage.

In one aspect, an apparatus is provided in the form of an interface. Acomponent is operatively coupled to the substrate in a first position,and the interface is configured in communication with the component in afirst state. The interface comprises a resilient material. Responsive toexposure of the interface to a thermal event above a first temperature,the resilient material changes from the first state to a second state.The second state includes a physical transformation of the resilientmaterial. The transformation changes the position of the component fromthe first position to a second position, wherein the second position isa separation of the component from the substrate.

These and other features and advantages will become apparent from thefollowing detailed description of the presently preferred embodiment(s),taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The drawings referenced herein form a part of the specification.Features shown in the drawings are meant as illustrative of only someembodiments, and not of all embodiments, unless otherwise explicitlyindicated.

FIG. 1 depicts a block diagram illustrating positioning of discretecomponents to the substrate together with an interface, with theconfiguration limiting damage to an associated substrate responsive toexposure of the interface to a thermal event.

FIG. 2 depicts a block diagram illustrating separation of a failingcomponent from the substrate upon exposure to the thermal event.

FIG. 3 depicts a block diagram illustrating positioning of the interfacewith respect to a discrete component responsive to exposure of thecomponent to the thermal event.

FIG. 4 depicts a block diagram illustrating separation of the failingcomponent from the substrate upon exposure to the thermal event.

FIG. 5 depicts a flow chart illustrating a process for mitigating damageto the substrate upon exposure to the thermal event.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentembodiments, as generally described and illustrated in the Figuresherein, may be arranged and designed in a wide variety of differentconfigurations. Thus, the following detailed description of theembodiments of the apparatus, system, and method of the presentembodiments, as presented in the Figures, is not intended to limit thescope of the embodiments, as claimed, but is merely representative ofselected embodiments.

Reference throughout this specification to “a select embodiment,” “oneembodiment,” or “an embodiment” means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present embodiments. Thus,appearances of the phrases “a select embodiment,” “in one embodiment,”or “in an embodiment” in various places throughout this specificationare not necessarily referring to the same embodiment.

The illustrated embodiments will be best understood by reference to thedrawings, wherein like parts are designated by like numerals throughout.The following description is intended only by way of example, and simplyillustrates certain selected embodiments of devices, systems, andprocesses that are consistent with the embodiments as claimed herein.

Unless the meaning is clearly to the contrary, all references madeherein to ranges are to be understood as inclusive of the endpoints ofthe ranges. The modifier “about” used in connection with a quantity isinclusive of the stated value and has the meaning dictated by thecontext (e.g., includes the degree of error associated with measurementof the particular quantity). Unless the meaning is clearly to thecontrary, all references made herein to pressures, such as atmosphere(s)(atm), are to be understood as relative to atmospheric pressure.

Exposure of a substrate and/or a component positioned proximal to thesubstrate to a critical temperature can cause damage to the substrateand/or the component. Effects of the exposure may include, but are notlimited to, fire, smoke, spark, functionality loss, and/or deformation.In one embodiment, the component(s) and the substrate may have acritical temperature, with exposure to the critical temperature leadingto damage. Examples of the critical temperature include, but are notlimited to, exposure above about 1000 degrees Celsius and exposure aboveabout 500 degrees Celsius. Different components comprised of differentmaterials may have separate and unique critical temperatures. Forexample, component₀ may have a first critical temperature, temperature₀,and component₁ may have a second critical temperature, temperature₁,with temperature₀ and temperature₁ being different. Similarly, asubstrate in communication with both component₀ and component₁ may havea third critical temperature, temperature₂, that is different fromtemperature₀ and temperature₁. In one embodiment, at least one of thecomponents or substrate may have a matching critical temperature. In oneembodiment, individual components in communication with the substratemay have separate critical temperatures. Similarly, in one embodiment,the critical temperature of the substrate may be separate from thecritical temperature(s) of the components in communication with thesubstrate. In one embodiment, the critical temperature may be selectedfrom a lowest critical temperature of each of the components and thesubstrate. Accordingly, the critical temperature is a characteristic ofthe component(s) and/or substrate at which they are subject to failure.

A temperature increase on the substrate and/or component(s) may becaused by a variety of different factors including, but not limited to,a high current event and/or an electrical short. High current through aconductor on the substrate or in one of the components in communicationwith the substrate can lead to resistive heating causing temperatureincreases in the substrate and thermal runaway. For example, the thermalrunaway may be an increase in temperature of the conductor experiencingthe high current which leads to an increase in resistance of theconductor which causes further increases in temperatures.

The electrical short may be caused by, but is not limited to, acomponent operatively coupled to the substrate, solder bridging, and/ora component shift. The component operatively coupled to the substratemay have a short (e.g., lower resistance) leading to excessive heatingwithin the component and resultant thermal runaway. Solder bridgingoccurs when solder connects two conductors which were not designed to beconnected together and causes a lower resistance path (e.g., anelectrical short) for an electrical circuit. The component shift is whenthe component is misaligned with the electrical interface on thesubstrate due to movement of the component. For example, the componentmay shift from a first position to a second position during a solderreflow process. Accordingly, either an electrical short or a highcurrent event can lead to damage of the substrate and/or componentoperatively coupled to the substrate.

Damage (e.g., burns) to the substrate and/or operatively coupledcomponent includes, but is not limited to, smoke, fire, failure of thecomponent, failure of a portion of the substrate, failure of the entiresubstrate, and/or damage to surrounding devices. In one embodiment,damage may be caused by a discrete failure of a single component, andthe substrate may continue to function without the failing component.Accordingly, if the failure of the failing component can be mitigatedprior to causing damage to the substrate and/or other component(s), thedamage caused by the failure is limited, or in one embodiment isolated,and the substrate may remain operational and/or repairable.

Solutions to limit damage to the substrate due to a discrete failure areprovided, with embodiments directed at an apparatus and method asdiscussed below in detail. As shown and described, the apparatus isconfigured with an interface having a resilient material and atransition temperature above a first temperature. The transitiontemperature is a temperature at which the interface undergoes a statechange from a first state to a second state including changing theresilient material form a first state to a second state. It isunderstood that solder may be employed to mechanically and/orelectrically attach electronic components to a printed circuit board(PCB). With that in mind, the first temperature may be a liquidustemperature of an associated solder material employed to operativelybond the component to the substrate such that the first temperatureweakens the mechanical attachment created by the solder.

Exposure of the interface to a thermal event that meets or exceeds thetransition temperature of the device causes the resilient material tophysically transform from a first state to a second state. In oneembodiment, the thermal event is an increase in temperature that meetsor exceeds a first temperature caused by an electrical short. In oneembodiment, the electrical short is in the component. The transformationalters a physical position of the component in relation to thesubstrate. More specifically, prior to the transformation, the componentis in a first position in relation to the substrate, and after thetransformation, the component is in a second position in relation to thesubstrate. In the first position, the component is mechanically and/orelectrically coupled to the substrate; in the second position, thecomponent is mechanically and/or electrically separated from thesubstrate. The separation of the component in the second position may bea partial separation or a complete separation. Regardless of thequantity of the separation, there is a disruption of the flow ofelectrical energy (e.g., decrease in current) between the component andthe substrate, with the disruption mitigating additional temperatureincrease of the component and/or substrate. In one embodiment, thedisruption limits damage to the discrete component and/or localizedarea. In one embodiment, the second position is an indication that thecomponent has experienced a failure, thereby facilitating the process oflocating and/or identifying the failing component. Accordingly,integration of the interface with the component and the substratemitigates damage to the substrate and/or component responsive to thethermal event.

Referring to FIG. 1, a block diagram (100) is provided illustratingpositioning of discrete components to the substrate together with theinterface. As described in detail below, the configuration functions tolimit damage to an associated substrate responsive to exposure of theinterface to a thermal event. As shown, a plurality of components (104a), (104 b), and (104 n), is adjacently positioned across a substrate(102). Each of the components (104 a)-(104 n) are operatively coupled tothe substrate (102), e.g. mechanically and electrically coupled to thesubstrate (102). As shown, each component (104 a)-(104 n) is in a firstposition relative to the substrate (102). The components may be, but arenot limited to, a resistor, a capacitor, an optoelectronic device, anoscillator, a connector, a potentiometer, an integrated circuit, asensor, a transducer, a relay, a switch, a driver, a motor, a powersupply, a transformer, and similar devices. Each component (104 a)-(104n) may be the same type of component or different types of components.In the first position, each component (104 a)-(104 n) is shown with aninterface (106 a)-(106 n) configured to an external surface (120 a)-(120n) of each component (104 a)-(104 n). As shown, component (104 a) isshown in communication with interface (106 a) configured to externalsurface (120 a), component (104 b) is shown in communication withinterface (106 b) configured to external surface (120 b), and component(104 n) is shown in communication with interface (106 n) configured toexternal surface (120 n). In one embodiment, the configuration of thecomponents (104 a)-(104) with the interfaces (106 a)-(106 n) may includea physical contact, however, the components may not be physicallyattached. In one embodiment, the configuration of the components (104a)-(104 n) with the interfaces (106 a)-(106 n) includes physical contactand a physical attachment. The physical attachment may be a mechanicalor a chemical attachment between the component and the interface. Forexample, the physical attachment may be, but is not limited to, amechanical fastener, a solder joint, and an adhesive. In one embodiment,interfaces (106 a)-(106 n) are selectively and individually configuredto components (104 a)-(104 n). For example, in one embodiment, at leastone component may not have an interface (106 a)-(106 n). The quantity ofcomponent(s), substrate(s), and interface(s) is for illustrationpurposes only and should not be considered limiting. Accordingly, theinterface for each component is configured in communication with anexternal surface of the component and effectively facilitates separationof the component(s) from an external surface (116) of the substrate(102).

Each interface (106 a)-(106 n) is configured to change states uponexposure of the interfaces (106 a)-(106 n) to a transition temperature.In one embodiment, the transition temperature is above a firsttemperature and below a critical temperature. Exposure of the substrate(102) to a critical temperature may cause damage to the substrate (102).The first temperature is defined as a temperature at which a physicalattachment (108 a) between the component (104 a) and the substrate (102)is mechanically weakened, as described in detail below. Accordingly, inthis example each component (104 a)-(104 n) is shown with an interface(106 a)-(106 n), respectively, applied to an external surface (120a)-(120 n) of the associated component, with each interface (106 a)-(106n) positioned between the associated component and the substrate (102).

Each interface (106 a)-(106 n) is configured with a resilient material.The transition temperature of the interface may correspond to atransition temperature of the resilient material. The resilient materialmay be, but is not limited to, a shape memory alloy, a spring, and apolymer. In one embodiment, the shape memory alloy may be but is notlimited to, a nickel titanium (NiTi) based alloy and a nickel titaniumhafnium (NiTiHf) based alloy. In one embodiment, the NiTi and/or NiTiHfalloy additionally includes, but is not limited to, gold, palladium,platinum, and zirconium. In one embodiment, the transition temperatureof the resilient material is above about 270 degrees Celsius and belowabout 400 degrees Celsius. For example, the composition of a NiTiHfalloy can be selected in order to achieve an optimal transitiontemperature. In one embodiment, the transition temperature of theresilient material can withstand a solder reflow operation withoutpremature transformation of the resilient material. In one embodiment,the transition temperature, the critical temperature, and the firsttemperature are measured at one atmosphere of absolute pressure. In oneembodiment, each component (104 a)-(104 n) may receive an interface (106a)-(106 n) with a distinct resilient material composition. For example,the resilient material composition for an individual component may beselected based on a property of the component. Similarly, in oneembodiment, the resilient material composition may be selected based ona property of the substrate, or based on a combination of the propertyof the component and the substrate. Accordingly, the interfaces (106a)-(106 n) comprise a resilient material configured to physicallytransform from a first state to a second state before the substrate(102) is exposed to a critical temperature.

In one embodiment, the resilient material may be encapsulated in asecondary body and the transition temperature of the interface maycorrespond to the transition temperature of the secondary body. Thesecondary body may be any material which maintains the resilientmaterial in a first state by encapsulation. The transition temperatureof the secondary body is a temperature at which the encapsulation by thesecondary body is degraded. Upon degradation of the encapsulation by thesecondary body, the resilient material may exert a force which overcomesthe encapsulation by the secondary body and the resilient materialtransforms to the second state. For example, in one embodiment, theinterface is a spring encapsulated in a secondary material which is aplastic material. The plastic material may be comprised of, but is notlimited to, acrylic, nylon, polyamide-imide, polyarylate,tetrafluoroethylene, polybutylene terephthalate,polycyclohexylenedimethylene terephthalate, polyetheretherketone,polyethylene terephthalate, polycarbonate, polyetherimide, polysulfone,and poly(p-phenylene oxide). In one embodiment, the secondary body has atransition temperature above about 270 degrees Celsius and below about500 degrees Celsius. The transition temperature may be, but is notlimited to, a melting temperature, a glass transition temperature, and adeformation temperature. For example, acrylic has a transitiontemperature of 260 degrees Celsius, nylon has a transition temperatureof 270 degrees Celsius, polyamide-imide has a transition temperature of340 degrees Celsius, polyarylate has a transition temperature of 370degrees Celsius, tetrafluoroethylene has a transition temperature of 320degrees Celsius, polybutylene terephthalate has a transition temperatureof 260 degrees Celsius, polycyclohexylenedimethylene terephthalate has atransition temperature of 300 degrees Celsius, polyetheretherketone hasa transition temperature of 380 degrees Celsius, polyethyleneterephthalate has a transition temperature of 280 degrees Celsius,polycarbonate has a transition temperature of 290 degrees Celsius,polyetherimide has a transition temperature of 370 degrees Celsius,polysulfone has a transition temperature of 370 degrees Celsius, andpoly(p-phenylene oxide) has a transition temperature of 300 degreesCelsius.

At temperatures below the transition temperature of the secondary body,the secondary body is in a first state and the encapsulation of theresilient material by the physical structure of the secondary bodymaintains the first state of the resilient material. Upon meeting orexceeding the transition temperature, the physical structure of thesecondary body transforms to the second state with the transformationincluding a weakening of the encapsulation by the secondary body of theresilient material. The transformation may include a softening or amelting of the secondary body. Due to the weakened physical structure ofthe secondary body, the resilient material is either partiallyencapsulated or no longer encapsulated by the secondary body and theforce exerted by resilient material transforms the resilient material tothe second state. In one embodiment, the transition temperature of thesecondary body can withstand a solder reflow operation without prematureweakening of the encapsulation. In one embodiment, each component (104a)-(104 n) may receive an independent interface (106 a)-(106 n) with adistinct secondary body composition. For example, the secondary bodycomposition may be tailored based on a property of the component.Accordingly, the interfaces (106 a)-(106 n) may comprise a secondarybody configured to release the resilient material, with the release tophysically transform before the substrate (102).

As shown, contacts are provided for each component (104 a)-(104 n) tosupport securing the component to the substrate (102) together withenabling electrical communication with the substrate (102). Morespecifically, component (104 a) includes contacts (112 a) and (114 a),component (104 b) includes contacts (112 b) and (114 b), and component(104 n) includes contacts (112 n) and (114 n). Each of the contacts (112a)-(112 n) and (114 a)-(114 n) are positioned on the external surface(116) of the substrate (102). Furthermore, as shown herein, each of thecontacts (112 a)-(112 n) and (114 a)-(114 n) are in a first positionrelative to the substrate (102). The quantity of contact(s) is forillustration purposes and should not be considered limiting.Accordingly, prior to exposure to a thermal event, each component (104a)-(104 n) is electrically and mechanically provided in a first positionand in communication with the substrate (102).

The substrate (102) may be, but is not limited to, a printed circuitboard (PCB), an interposer, and a motherboard. The component contacts(112 a)-(112 n) may be operatively coupled to the substrate (102) byphysical attachments (108 a)-(108 n), respectively. In one embodiment,component contacts (114 a)-(114 n) may be operatively coupled tosubstrate (102) by physical attachments (110 a)-(110 n), respectively.The interfaces (106 a)-(106 n) are positioned adjacent to the substrate(102). In one embodiment, the interfaces (106 a)-(106 n) are configuredto substrate (102) and positioned adjacent to the components (104a)-(104 n). In one embodiment, components (104 a)-(104 n) are attachedto substrate (102) by a solder reflow process. Accordingly, thecomponents (104 a)-(104 n) are operatively coupled to the substrate(102) with an interface (106 a)-(106 n) positioned between thecomponents (104 a)-(104 n) and the substrate (102), respectively.

During a solder reflow process, a conductive material is placed on theexternal surface (116) of the substrate (102). The solder is placed atone or more designated locations (e.g. electrical interface pattern) onthe substrate (102) to which the contacts (112 a)-(112 n) and (114a)-(114 n) of the components (104 a)-(104 n) are to be attached to thesubstrate (102). The components (104 a)-(104 n) are placed incommunication with, e.g. onto, the substrate (102) with conductivematerial residing between component contacts (112 a)-(112 n) and (114a)-(114 n) and the electrical interface pattern on the external surface(116) of the substrate (102). An assembly of the substrate (102) andcomponents (104 a)-(104 n) is subject to a heating process where theassembly encounters a profile of a rising or increased temperature, thatin one embodiment reaches a peak temperature above the solder reflowtemperature (e.g. liquidus temperature of the conductive material). Atthe peak temperature, the conductive material is subject to a softeningor in one embodiment, melting, and an electrical connection between thecomponents (104 a)-(104 n) and the electrical interface pattern may beestablished. In one embodiment, the peak temperature is below thetransition temperature of the interfaces (106 a)-(106 n) to preventpremature state changes (e.g. changes in operating states) of theinterfaces (106 a)-(106 n).

The solder reflow process is concluded with a cool down period where theconductive material changes to a solid phase (e.g. below the liquidustemperature of the conductive material) to form one or more physical andelectrical joints (108 a)-(108 n) and (110 a)-(110 n). The conductivematerial may be, but is not limited to, leaded solder, lead free solder,solder paste, solder wire, and conductive adhesives. In one embodiment,the conductive material is solder composed of 63 weight percent tin and37 weight percent lead and has a reflow temperature of 183 degreesCelsius. In one embodiment, the solder joints (108 a)-(108 n) and (110a)-(110 n) form an electrical connection between the components (104a)-(104 n) and the substrate (102). In one embodiment, the firsttemperature is the liquidus temperature of solder in at least one of thesolder joints (108 a)-(108 n) and (110 a)-(110 n). Accordingly, thesolder joints (108 a)-(108 n) and (110 a)-(110 n) may electrically andmechanically attach the components (104 a)-(104 n) to the substrate(102).

Referring to FIG. 1, the solder joints (108 a)-(108 n) and (110 a)-(110n) and interfaces (106 a)-(106 n) are at an operating temperature andthe resilient material within interfaces (106 a)-(106 n) is in a firststate. The operating temperature is a temperature at which theelectrical circuit formed between each component (104 a)-(104 n) and thesubstrate (102) is functional. The operating temperature may be atemperature below about 150 degrees Celsius. The substrate (102) mayexperience damage if the substrate (102) is exposed to a criticaltemperature. For example, a critical temperature may be caused by a highcurrent event and/or an electrical short in the substrate (102) and/orthe components (104 a)-(104 n). In order to mitigate potential damage tothe substrate (102), the resilient material in the interfaces (106a)-(106 n) is configured to undergo a state change prior to reaching acritical temperature.

For example, in one embodiment, component (104 a) experience anelectrical short while components (104 b)-(104 n) are not or have notexperienced an electrical short. If the electrical short causes thesubstrate (102) to reach a critical temperature, the functionalityand/or physical characteristics of the substrate (102) and/or components(104 a)-(104 n) may be affected. However, if the discrete failingcomponent (104 a) is separated from the substrate (102) before acritical temperature is reached, the substrate (102) may not be affectedby the thermal event caused by the electrical short of component (104 a)and as such the substrate (102) and components (104 b)-(104 n) maycontinue to operate without component (104 a). In one embodiment, (104b) is a backup component for (104 a). In one embodiment, components (104a) and (104 b) are different components. Separation of an individualcomponent, such as component (104 a) is referred to herein as a discreteremoval, which effectively limits removal to an individual component.Accordingly, discrete removal of component (104 a) mitigates potentialdamage to the substrate (102) and/or non-failing components (104 b)-(104n).

Referring to FIG. 2, a block diagram (200) is provided illustratingseparation of a failing component from the substrate upon exposure to athermal event. As shown, an electrical short in component (204 a)exposes interface (206 a) and solder joints (208 a) and (210 a) to athermal event. The thermal event causes the temperature of solder joints(208 a) and (210 a) to increase from the operating temperature to asecond temperature above the liquidus temperature of the solder insolder joints (208 a) and (210 a). This increase of the temperaturecauses a softening and/or melting of solder joints (208 a) and (210 a)to where the physical attachment between component (204 a) and thesubstrate (202) is weakened. The thermal event causes the temperature ofthe interface (206 a) to increase from the operating temperature to thesecond temperature which meets or exceeds the transition temperature ofthe interface. Exposure of the interface (206 a) to the thermal eventcauses the resilient material to undergo a physical transformation,including changing the resilient material from the first state to asecond state. In one embodiment, the state change is caused by asoftening and/or melting of a secondary material encapsulating theresilient material within interface (206 a). In one embodiment, thestate change is caused by a physical shape change in the resilientmaterial. Accordingly, subjecting the resilient material to the thermalevent causes the interface (206 a) to physically transform from a firststate to a second state.

Due to the weakened physical attachment of the component to thesubstrate, the second state of the resilient material within interface(206 a) alters the position of the component (204 a). This alteredposition is also referred to herein as a second position, whichseparates component (204 a) from the external surface (216) of substrate(202). The separation includes an interruption of at least one of thesolder joints (208 a) and (210 a). This interruption is an electricaldisruption of the electrical connection between the component (204 a)and substrate (202). The separation is caused by a force associated withthe state change of the resilient material. In one embodiment, the statechange of the resilient material includes an increase in a physicaldimension of the resilient material. The force exerted by the resilientmaterial effectively pushes on the external surface (220 a) of thecomponent (204) which causes the position of the component (204) to moveaway from the substrate (202). The disruption of the electricalconnection caused by the force mitigates the electrical short in thecomponent (204 a), which limits any further temperature increases to thesubstrate (202) and/or component (204 a) caused by the electrical short.In one embodiment, the resilient material remains in the second stateeven after cooling below the transition temperature. In one embodiment,the resilient material is reusable and returns to the first state aftercooling below the transition temperature. In one embodiment, the firstand second states are configurations of the resilient material within asingle phase of matter (e.g. solid). Accordingly, the resilient materialdiscretely separates the component experiencing the thermal event fromthe substrate in order to mitigate and/or localize potential damage.

Referring to FIG. 3, a block diagram (300) is provided illustratingpositioning an interface with respect to a discrete component responsiveto exposure of the component to a thermal event. As shown, component(304) is operatively coupled to substrate (302). More specifically,component (304) is shown herein in a first position relative to thesubstrate (102) in a first state. In the first position, an externalsurface of component (304) is configured in communication with aninterface (306). Similarly, in the first state, the interface (306) ispositioned on an external surface (322) of the component (304) distal tosubstrate (302), and the interface (306) is operatively coupled (e.g.physically attached) to a secondary surface (318) and the component(304). Accordingly, the interface (304) is configured independent of thesubstrate (302), and in the first state the interface (304) isconfigured in communication with component (304) and secondary surface(318).

As shown, contacts (312) and (314) are provided for component (304) tosupport securing the component to the substrate (302) together withenabling electrical communication of component (304) with the substrate(302). Each of the contacts (312) and (314) are positioned incommunication with the external surface (316) of the substrate (102). Inone embodiment, each contact (312) and (314) extend into one or layersof substrate (102). The interface (306) comprises a resilient materialin a first state that is configured to change states in response toexposure of the interface (306) to a transition temperature. In oneembodiment, the transition temperature is above a first temperature andbelow a critical temperature. The first temperature may be a temperatureat which solder joints (308) and/or (310) are mechanically weakened. Thequantity of component(s), substrate(s), contact(s), and interface(s) isfor illustration purposes only and should not be considered limiting.Accordingly, prior to exposure of component (304) to a thermal event,component (304) is shown in a first state in which the component iselectrically and mechanically provided in a first position and incommunication with the substrate (302).

Furthermore, in the first state, solder joints (308) and (310) andinterface (306) are at an operating temperature. In one embodiment,component (304) experiences an electrical short and the position of thecomponent in relation to the substrate is subject to change. Referringto FIG. 4, a block diagram (400) is provided illustrating separation ofa failing component from the substrate upon exposure to a thermal eventin order to limit damage to the substrate, and effectively demonstratinga state change of the component from the first state to a second state.As shown, the electrical short in component (404) exposes interface(406) and solder joints (408) and (410) to a thermal event. The thermalevent causes the temperature of solder joints (408) and (410) toincrease from the operating temperature to a second temperature abovethe liquidus temperature of the solder in solder joints (408) and (410).The thermal event softens and/or melts solder joints (408) and (410) towhere the physical attachment to the substrate (402) is weakened. Thethermal event causes the temperature of the resilient material withininterface (406) to increase from the operating temperature to the secondtemperature which meets or exceeds the transition temperature of theinterface (406). Exposure of the interface (406) to the thermal eventcauses the resilient material to undergo a physical transformation,including changing the resilient material from the first state to asecond state. Accordingly, the thermal event causes the resilientmaterial of the interface (406) to physically transform from the firststate to the second state.

Due to the weakened physical attachment between the component (404) andthe substrate (402), the second state of the resilient material withininterface (406) alters the position of the component (404). This alteredposition is also referred to herein as a second position, whichseparates component (404) from the external surface (416) of substrate(402). In one embodiment, the separation is caused by a force in theform of a decrease in a dimension of the resilient material. Theresilient material exerts a force which pulls) on external surface (422)of the component (404) which causes the position of the component (404)to move away from the substrate (402). The separation includes aninterruption of at least one solder joint, e.g. solder joints (408) and(410), from the substrate (402) and a disruption of the electricalconnection between the component (404) and substrate (402). Thedisruption of the electrical connection mitigates the electrical shortin the component (404), which limits any further temperature increasesto the substrate (402) and/or component (404) caused by the electricalshort. Accordingly, the resilient material discretely separates thecomponent experiencing the thermal event from the substrate in order tomitigate and/or localize potential damage.

As shown and described in FIG. 4, the state change results in a forceexerted by the resilient material effectively pulling the component(404) away from the substrate (402). In one embodiment, the resilientmaterial of the interfaces (106 a) and (306) may be exerting a force onthe components (104 a) and (304), respectively in the first position.The force exerted by the resilient material of interfaces (106 a) and(306) is counteracted by the physical attachment between the components(104 a) and (304) and substrates (102) and (302), respectively, due tothe physical attachment created by solder joints (108 a), (110 a), (308a), and (310 a). However, when solder joints (108 a), (110 a), (308 a),and (310 a) are exposed to at least the liquidus temperature of thesolder within the respective joints, the solder joints (108 a), (110 a),(308 a), and (310 a) soften and/or melt. This softening and/or meltingweakens the physical attachment between the components (104 a) and (304)and the substrates (102) and (302), respectively. The weakened physicalattachment causes the force exerted by the resilient material of theinterfaces (106 a) and (306) to change the position of the components(104 a) and (304) from the first position to the second position. Asdescribed above, in the second position components (104 a) and (304) areseparated from external surfaces (116), and (316) of substrate (102) and(302) respectively. The second position is shown in detail as components(204 a) in FIG. 2 and (404) in FIG. 4. The separation includes aninterruption of at least one solder joint from solder joints (208 a) and(210 a), and (408) and (410). The interruption includes a disruption ofthe electrical connection between the components (204 a) and (404) andsubstrates (202) and (402), respectively. In one embodiment, theresilient material may be, but is not limited to a spring, an adhesivestrip, a metallic strip, and a bimetallic adhesive strip. Accordingly,the resilient material discretely separates the component experiencingthe thermal event from the substrate in order to mitigate and/orlocalize potential damage.

Referring to FIG. 5, a flow chart (500) is provided illustrating aprocess for mitigating damage to a substrate upon exposure to a thermalevent. As shown, a component is provided and prepared to be configuredwith an interface (502). The interface is configured in communicationwith the component in a first state (504). The interface comprises atleast one resilient material in a first state. The resilient material isconfigured to state change, e.g. from the first state to a second state,in response to exposure of the interface to a transition temperatureabove a first temperature and less than a critical temperature. In oneembodiment, the critical temperature will cause damage to the substrateand/or the component. The first temperature is a temperature ortemperature range which weakens a mechanical attachment between thecomponent and the substrate. In one embodiment, the first temperature isthe liquidus temperature of solder used to mechanically and electricallyattach the component to the substrate. Following configuration of theinterface to the component at step (504), the component is operativelycoupled to the substrate in a first position, and in one embodiment, theinterface is positioned adjacent to the substrate (506). In oneembodiment, at step (506) the interface is positioned distal to thesubstrate and operatively coupled to a secondary surface of a tertiarybody. In one embodiment, the process shown in step (506) includes asolder reflow process and the forming of a solder joint between thecomponent and the substrate. Formation of the solder joint includescreating an electrical connection between the substrate and thecomponent (508). In one embodiment, the solder joint creates amechanical attachment between the component and the substrate.Accordingly, following step (506) the substrate and component arephysically attached and an electrical circuit created between thesubstrate and the component is operational.

The interface is subjected to a thermal event that meets or exceeds thetransition temperature of the interface (510). The thermal event may becaused by an electrical short in the component and/or substrate.Responsive to the thermal event, the mechanical connection between thecomponent and the substrate is weakened (512). In one embodiment, theweakened connection may include a softening and/or melting of the solderjoint (512). The resilient material within the interface is subjected toa state change that includes changing the resilient material from thefirst state to a second state (514). The state change physicallytransforms the resilient material, with the transformation altering aposition of the component from the first position to a second position,and includes separating the component from the substrate (516). Thisseparation interrupts the solder joint (518) and breaks the electricalcircuit formed between the component and the substrate. In addition, thesolder joint separation causes the electrical circuit to benon-operational (520). The disruption of the electrical circuitmitigates damage associated with the electrical short. Morespecifically, the disruption of the electrical communications betweenthe substrate and the component limits further temperature increases tothe substrate and/or component which may cause damage to the affectedcomponent, other components, and/or substrate. Accordingly, theinterface is configured with a resilient material which enables discreteseparation of the component from the substrate in order to isolatedamage caused by the electrical short to the affect component.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the embodiments.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present embodiments has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the embodiments in the form disclosed.

The description of the present embodiments has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the embodiments in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of theembodiments. The embodiments were chosen and described in order to bestexplain the principles of the embodiments and the practical application,and to enable others of ordinary skill in the art to understand theembodiments for various embodiments with various modifications as aresuited to the particular use contemplated. Accordingly, theimplementation of an interface with a resilient material configured toundergo a state change can be used to limit damage to a discretecomponent of a substrate.

It will be appreciated that, although specific embodiments have beendescribed herein for purposes of illustration, various modifications maybe made without departing from the spirit and scope of the embodiments.In particular, any type of components may be used in association withthe spirit and scope of the embodiment. The component may be, but is notlimited to, an electrical device, a socket, and or a mechanicalattachment between a secondary body and a substrate. Additionally, theembodiments may apply to non-electronic heat sensitive componentspositioned in communication with or operatively coupled to a substrate.Accordingly, the scope of protection of the embodiments is limited onlyby the following claims and their equivalents.

What is claimed is:
 1. An apparatus comprising: a component operativelycoupled to a substrate in a first position; an interface configured incommunication with the component in a first state, the interfacecomprised of a resilient material; responsive to exposure of theinterface to a thermal event above a first temperature, the resilientmaterial configured to change from the first state to a second state,the second state including a physical transformation of the resilientmaterial; and the transformation to change a position of the componentfrom the first position to a second position, wherein the secondposition is a separation of the component from the substrate.
 2. Theapparatus of claim 1, wherein the resilient material is a shape memoryalloy and wherein a transition temperature of the shape memory alloy isabove the first temperature.
 3. The apparatus of claim 2, wherein thetransition temperature is above about 270 degrees Celsius and belowabout 400 degrees Celsius.
 4. The apparatus of claim 1, wherein theresilient material is encapsulated in a body and wherein the physicalformation change includes a softening of the body.
 5. The apparatus ofclaim 4, wherein softening of the body occurs above about 270 degreesCelsius and less than about 400 degrees Celsius.
 6. The apparatus ofclaim 1, wherein the component includes an attachment to secure thecomponent to the substrate.
 7. The apparatus of claim 6, wherein theattachment is a solder joint, and wherein the separation includes aninterruption of the solder joint.
 8. The apparatus of claim 7, whereinthe thermal event is in response to an electrical short in thecomponent.
 9. The apparatus of claim 8, further comprising anon-shorting component operatively coupled to the substrate; and whereinthe formation change is limited to separation of the component from thesubstrate, wherein the non-shorting component remains operativelycoupled to the substrate.
 10. The apparatus of claim 9, wherein thethermal event includes a temperature increase of a part to a secondtemperature above a solder reflow temperature and below a criticaltemperature of the substrate, wherein the part is selected from thegroup consisting of: the substrate and the component.